Recently, production of a large amount of monospecific antibody against P. berghei sporozoite membrane components has been achieved by hybrization of sporozoite antibody-producing murine spleen cells with plasmacytoma. Similarly, a large amount of monospecific antibodies against the surface antigens of Plasmodium gallinaceum gametes and against those of P. knowlesi erythrocytic merozoites has been produced by using hybridoma. For the coming year, we will study by immunoelectron microscopy and freeze-etching techniques, the specificity and the distribution of these hybridoma-derived antibodies on the surface of the Plasmodium gametes and merozoites.